Gasolene rock-drill.



H. s. TROU. GASOLENE ROCK DRILL.

APPLICT'ION FILED APR. 25. i917.

1,286,152. Patented Nov. 26, 1918.

UNHED STATES ATQENT OFFIG. r.

ROLLAND s. TROTT, Lor DENVER, COLORADO.

GASOLENE ROCK-DRILL.

To all whom t may concern Be it known that I, ROLLAND S. TRo'r'r, a citizen of the United States, residing at Denver', State of Colorado, have invented certain new and useful Improvements in Gasolene Rock-Drills, of which the following is a specification.

The first object of the invention is to provide a gasolene rock drill which, because of its design will not receive the' enormous shocks sustained by other such drills, and will therefore be more reliable and less subject to breakage.

A further object is to provide means whereby the troubles due to the rear air cushion between the fixed stroke piston and the floating piston, (which in Trott, 915,320, Mar. 16th, 09, and in Scott, 1,058,268, April Sth, 1913, must bear the force of the explosion as well as the force of-cushioning the return of the xed stroke piston against the floating piston), will be overcome.

A further'obj'ect is to povide means whereby a greater number of blows may be struck per minute, through the reduction in reciprocating weight. y

A further object is -through providing means for more blows per minute, to thereby give less timefor each blow and hence less time for air cushion leakage, so that more perfect and reliable cushioning may be obtained with the same clearances between parts.

A further' object is to provide means whereby the piston which acts as the hammer may be made in one piece, thereby overcoming the various troubles brought on by built-up hammers.

A further object is to provide a construction whereby the compression space for the explosive gas in the cylinder above the piston is constant and this regardless of the cushioning meals between the fixed stroke piston and the floating piston, whereby constant conditions for the operation of the gas engine part of the drill may-be obtained.

A further object is to provide means whereby the piston which acts as the ham-.

mer may be made much lighter than is possible with the required strength in either. the Trott or the Scott constructions mentioned above.

A further obje-ct is to provide means so Specification of Letters Patent.

Patenten Nov. 26, 1918.

i Alipncaaon med Aprn as, 1917. serial No. 194,488.

that a light weight hammer by striking more blows may do as much or more drilling than a heavier hammer striking fewer blows.

A further object is to provide means whereby with more blows per minute,rless time for cushion leakage, and lighter reciprocating weights, the internal shocks to the drill will not only be less, but they will be more perfectly cushioned in addition.

A further object is to provide means whereby because of the very long cross-head furnished by the fixed stroke piston, andibecauso the blow-striking can have no rotative effect upon it, no piston pin guides are required, thus allowing for`a light rolling or rotative movement of the fixed stroke piston should any such be necessary in order to overcome any small inequalities of stroke or lalinement of the two cranks, or any misalinement due to faulty machine work or wea-r.

A further object is to provide means whereby the slots in the external piston, a source of great weakness in the design, may be done away with, thus allowing equal strength with a much lighter external piston, .which means lighter reciprocating weight.

In the drawings, Figure 1. is a section on a vertical longitudinal plane; and Fig. 2. is a top elevation with partial section.

In Fig. 1 it will be seen that the water jacketed cylinder l, is provided with exhaust ports '2 and by-pass ports 3, a mixing valve 4, spark plug 5 and spark timer 6,- all substantially the same as in the ordinary pressed into and exhausted out of the hollow, 9C, of the piston, 9on each revolution, thus forming a positive means of cooling both the head of the piston, 9, and the rear cushion of the hammer, 14.

Connecting rods, 10, connect the piston pin, 8, with the cranks, 11, of the cranklof the cylinder, charge at that point.

The construction thus far described 'will 4run as an ordinary two cycle engine; 1t is entirely independent ofthe striking mecha- `nism as far as running is concerned. The

' fixed stroke piston, 9, by its direct connection with the crankshaft, 12, will leave ex actly the same compression space in the cylinder on each backward stroke; and the explosive force will all be directly expended upon moving forward the fixed stroke piston, 9, and the shaft, 12, without any intermediate cushioning, and its attendant trou bles.

Because of this constant compression space, and the constant relation between the explosion and the crankshaft, the engine will run steadily, and its running will be in no way affected by the efficiency of the cushioning of the drilling part of the construction.

The floating piston or hammer, 14, is located partly inside and partly outside of the fixed stroke piston, 9, the hammer flange, 14a, fitting slidingly but closely 9d', of the piston, 9, and the hammer bar, 14", fitting slidingly but closely through the header, 15, and extending forward outside of the piston, 9.

It will be seen that because of this construction, the hammer flange, 14, has an air cushion on either side of it.

The small holes, 16, through the walls of the piston, 9, are to allow part of the explosive mixture to enter the hollow, 9d, on either side of the hammer flange, 14, and act as an air cushion, as a cooling means, and at the same time to lubricate the surfaces with oil that is drawn into the engine with the charge. p

The rotation shaft, 17, is revolved from the crankshaft, 12, by means of Itwo sprockets and a chain, 18; and its worm, I17, meshing with the gear, '19. on the chuck. 20, revolves the chuck, and thus the drill steel. 20a.

The spark timer, (i, is mounted on the.

rotation shaft, 17, and is to be connected by the usual hatteri'es. coil, and wire to give, a properly timed spark at the .spark plug,

It. will he seen that upon each backward 4stroke (see arrow il) ol' the fixed stroke piston. the gas m the c vllnder is compressed, the spark explodes the charge. and the piston, 9, is driven forward. revolving the shaft, 1Q, hy means ot' the rods. lo: the exhaust passes out of the ports. 2. and the fresh charge which-has been compressed in front ofthe piston. Sl. hy its forward stroke. sweeps in thrfmgh. the bv-pass ports. Land is` directed up into the cylinder hy the baille plate, 9". (rn the head of the piston. 9.' rl`he inertia, of the flywheels,

in the bore,

21, acting through the rods, 10, now returns the piston, 9, on the next back st'A oke, this acting to suck in the next fresh charge through the mixing valve, 4; the compressed charge in the cylinder is then fired by the spark, driving the piston, 9, forward, and so on.

When the piston, 9, stops atthe end of the back stroke, the hammer, 14, continues on backward, compressing the gas back of it into a cushion. l/Vhen the pressure of'this cushion gets great enough the backward movement of the hammer, 14, is stopped.

lVhen the hammer, 14, is in thisbackward position, the forward set of holes, 16, will be uncovered, and the space in front of the hammer flange, 14a, and inside of the piston, 9, will be filled, with gas. As the piston, 9, now travels forward the hammer, 14, will move forward also, impelled by the highly compressed cushion behind it. When the piston, 9, reaches the end of'- its forward stroke, the hammer, 14, will continue on forward till it strikes the hammer block, 13, against which the drill steel vis pressed. Thus the blow that does the ldrilling is struck.

On this further independent forward stroke of the hammer, 14, it compresses the gas in front of the flange, 14, against the header, 15, which is mounted'in the front end of the piston, 9, and when the piston,

pressure is increased till it is great enough to move vthe hammer, 14, backward. When the hammer, 14, is in this forward position, the backward set of holes, 16, through the walls of the piston, 9, willbe uncovered and gas ,will be forced into the piston, 9, back of the hammer flange, 14

Thus it will be seen that in my improved 9, moves' on its next backward stroke this which means three or four pounds of .veight instead of the ten or twelve pounds required when the hammer is external and has to be slotted. This light hammer, besides having` no weak spots due to slots, will put comparatirely little strain on the cushions;

Athe higher speed allowed hy the reduction in reciprocating weightwill maintain the cushioning more/perfectly with the same clearances between parts; and since the force of a blow varies with the square of the striking velocity oll the hammer, the lighter` hammer at higher speed will strike,as hardas the heavier slower lmnlmer. lt will also he seen that the force of the. explosion is not transmitted to the shaft, through any -cushion` which always means trouble with the cushion, hut is transmitted direct, through the external piston and the rods, to the sha t't. lt -will also be seen that the cushions are cooled and oiled positively by the mixture and the oil drawnin with it, and that the heat of the explosion is pre\fcnted from being carried to the cushions from the external piston head-'by means of a positively cooled intermediate insulatinglspace in the' external piston;

It should be-no'ted that the cushion back of the hammer flange, 14a, must stop the backward travel of the hammer, la, unassisted'; whilethe cushion in front of the flange, `il?, as'a general thing is required only to-cus'hion the return of the piston, 9, against it, as the drill steel, 20, through the hammer block., 13, is what does most of the stopping of 'ther forward movement of the hammer, 14. lt will be seen that the area of the cushion back of the hammer flange, la, is greater than that in front of it by an amount equal to the area of the hammer bar, lll. Also, the gas that feeds the cushion back of the flange, lla, is under com pression due to the forward stroke of the piston, 9; while the gas that feeds the cushion in front of the flange, lla, is somewhat rarelied because of the suction on the mixing valve: this difference between the compression and the suction tends to help the difference in areas of the two cushions in making the backward cushion much stronger than vthe forward cushion, as it should be.y

This not only gives a bettery cushion onL the back strokefwhere it is needed, but a freer blow at the endv of the forward stroke,

which is desired.v l

lt. will beseen that the exact tiniing and the proportions of these various 'operations mentioned above, will var v according to a good many factors, such as, weight of the hammer, il; position, number, and size of the holes, 16; amount ofcompression space in front of the piston, 9; number of blows per minute; length'of cushions on each side of the hammer flange, lla; length of hammer bar, 1lb: length of hammer block, 13, and its position as determined at will by the drill operator, etc.

rTherefore, l do not wish to confine my construction to any one set of conditions or proportions, out of the many under which my invention will satisfactorily operate; but what l Claim, is

l. ln an explosive engine, the combination of a two cycle ported cylinder having a combustion chamber, a hollow piston within the cylinder, a partition dividing` said piston into two chambers, a tloating piston parti)Y within the chamber farthest from the combustion chamber and adapted to operate ,a drilling device, a shaft. and means for operating the shaft connected to the hollow piston adpiccnt the partition.

The combination of a hollow piston divided into two chambers b v a partition, a floating hammer piston partly within one of said chambers, and a piston pin adjacent the partition of the hollow piston.

i 3. In an internal combustion rock drilling engine, the combination of a cylinder ported for intake a1 td by-pass of explosive mixture and exhaust at spent gases, an external fixed stroke pistol divided into two chambers by a partition, a floating piston operating partly withii the forward chamber of the said fixed stroke piston, said pistons being moved in e'al h. forward stroke by the explosion and exi ansion of gas within the cylinder, and a :rankshaft connected with the lixed stroke piston adjacent the partition and operabl; to move the pistons on the rearward stl oke.

l. In an e :plosive engine of the character'V described, tl e combination of a cylinder, a fixed stroke piston divided kby va partition into two clnmbers, a floating piston partly therein. sail pistons having differential movemenhsid cylinder being adapted for the explosioi of gas therein t0 move said pistons on cali-'l1 forward stroke, means for providing cushions between said pistons, a

shaft conne( ted to the fixed vstroke piston` adjacent tht partition and rotated by the fixed stroke piston onthe forward movement of the pistons and operating to return the pistons on the rearward stroke, and means for crntrolling the admission and exhaust of gas to and from the cylinder.

5. ln an explosive engine of the character described, de combination of a two cycle ported cylin ler. an external fixed stroke pisloo ported zylinder, an external fixed stroke piston divided by a partition into two chambers, and a partly inclosed floating piston in one of said chambers with which the floating piston cooperates, a shaft connected to tir;` external piston' adjacent the partition, a drill which is designed to be struck with the hamizier block, and means operated by the shaft for rotating said drill.

T. ln an internal combustion percussive engine of the character described, the combination with a drilling device of a two cycle poked and slotted cylinder. alb. external fixed stroke piston divided by a partition into two chambers. a floating piston arranged partly within said externa piston :ind adapted to deliver impact upon the drilling device. a. pin carried by said ex` ternal piston adjacent the partition and havingr its ends projecting through said cylinder slots.- a shaft, and connections between said pin and shaft for driving, the einer. y

s. ln an explosive'engine of the character -fixed stroke,

described, the combination of a two cycle ported cylinder, a'drilling device mounted at one end of the cylinder, .two pistons' mounted within the cylinder, one of said pistons being divided by a partition into t-Wo chambers, one of said pistonsbeing arranged partly Within4 the other, one-of said pistons being in the nature of a floating piston and designed to operate the drilling device, the other of said pistons having a a crankshaft operated by the last mentioned piston and adapted to move said pistons away from the drilling device, and meansfor providing cushions between saidl istons. 1

9. i described, the combination of a slotted cylinder, a drilling device mounted in one end of said cylinder, two pistons arranged withcylinder and connected to said shaft to. op-

erate same.l

10. In a percusslon engine of the characn an explosive engine of the character V the rearw'ar in carried.

ter described, the combination of a two cycle ported cylinder having an ber and a charge receiving chamber, means for introducing an ex losive fluid intotbe charge receiving chamber and transmitting said fluid -to said explosion chamber, two pistons arranged within the cylinder, o'ne of said pistons being mounted partly within the other, said pistonshaving relativelyv differential vmovement, one of said pistons being in the nature of a floating pisterand adapted to deliver impact', and the other havinga a partition into two chambers, a drilling device for receiving a, blow from the floating piston, and a crankshaft operated by the fixed stroke (piston for moving the pistons on stroke.

11. In a percussive engine ofthe character described, in combination, a two cycle ported cylinder provided Ywith an explosion chamber and 'a charge receiving chamber,

said chambers being' provided with means for'communication.whereby a char e may be conveyed from the latter to the former, an external fixed stroke piston divided Iby a Vpartition into two chambers within said cylinder, a fioating piston adapted to move with the said fixed stroke piston and to deliver blows, and a crankshaft operatively connected with said fixed strokepiston whereby vsaid pistons are. returned on their rearward stroke.

ROLLAND VS. TROTT.

explesion chamy fixed stroke and being divided by 

